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No. magos. Patented 1an. 3|,|s99. II. S. MAXIM. APPARATUS FOR MANUFACTURING FILAMEIITS FOR ELECTRIC LAMPS.

[Application led Nov. 8, 189B.) (No Modal.) 2 Sheets-Sheet I.

..32 @.5 k, )5. y s i ms persas co. Maremma. mswmcrrom o. c

No. s|8,7o3. Patented 1an. 3|, |899.

H. S. MAXLIrM'.

APPARATUS FOR IAIUFAO'WKHIE F'ILAIIENTS FOR ELECTRIC LAMPS.

[Application ined mw, s, 189s.) (No Nudel.) 2 Sheets-Sheet 2.

E Noam ill. li DS.

l forming port of Letters :Potent No, ljm, dated Jennery 3i, i899,

Application filed November S,y 189B. Scritti No. 695,833. (lle model!) ns inuch possible., rihis con only be done by nislrng them extremely line sud long or by @riding to the cnrbon of which they are composed seine highly-refractory non-conducting` materiel. lWhen such materiels es carbid el silicon and carbid of boron are eniployed with the carbon, they ere liable to be volotilized by the electric current when the lmnp is in nso ond to lorrn e thin ogeleseent ll'lin on the inside of the gloss globe of the lump. to this objection, it will endure o Verf)v high temperature Without boing,` Volutilized. Naturel diunontlowder-e'i. e7 naturel diemonde reduced to powder-isJ however, too exoensive to be used for this purpose even if inode from the cheapest hind ot' stones thst een be obtained; but according to my invention nur tble to manufacture eJ sneeies of carbon which, while closely if not completely resembling the disnionch will be less expensivei isn naturel dien'onds For this pun d a 'e it necessary to employ en extrcinelt7 rre 't nressure n high temperature, end of my invention hss er in which such groot t ereture ore obtained.

*iressure and l l lt is well known the' carbonio acid or cor bon dioxid {CO2} nis'y be retained in the liqm uid condition et n pressure of about freni fire hundred to six. hundred pounds per square inch ordinary temperatures, but lhot i; it be converted into eerbon niononid the pressure required to confine it is Very New diztniondpowder is not subject much greater., l telic advantage oi' this fact to obtain the hi gh pressure and temperature l require byplecingin e stron tightly-closed vessel carbonio acid in the liquid or solid conn dition7 together with carbon, preferebl7 ft hydrocarbon, such es gesolenec rihe enr# bouic scid und the hydrocarbon tre then dceoinposed by subjecting thorn to the Voltnic tre, the oxygen of the carbonio acid being` thus caused to telic up another measure of carbon and to be there'oyeonverted from con bon dionid4 into carbon xnonoid. This decomposition, together with the rise in tenin pereture, will produce the necessary pressure, the temperature o16 the carbon bein g et the seine time raised so extremely high that the carbon in ininicdiztte Contact with or contiguous to the electric conductors, between which the Volteic nrc is produced, will be con- Verted into e species of diztuiondecales which will scratch gloss, While all the enrbon will be Very inuchinodied.

in sonic instances it nir-y be necessary to continue the hi gh temperature for t Very lon time in order to allow the carbon to erystsh lize out of the cerboneceous gases. Of course if the carbon or hydrocarbon be heated in carbonio acid alone Very little effect Would telic place, ns no Very high pressure would be reached, Whereas if e too large quantity of hydrocarbon be employed t loose7 sinutty, end soft deposit would be formed; but by having only7 e smell excess of carbon-e'. e., just suflicient to convert all the carbonio scid present into carbon inonoxid with zt little Afree hydrocarbon reineiningmthen the crystallization inty take place frein the residuuni of gases, tud it the process be continued longn enough dieniondcrystels or a species of die inond-curbon may be formed. The diamondw carbon instead ol' being of et Very low resistonce, which is peculiar to carbon Whose tenin 'peinture hes been raised very high, will have imported to it e high quality oi electrica-'tl' re sistenee in feet, it insy be so perfectly cry/s tnllized es to altogether prevent the passage ol en electric current through it. rihis of course depends upon the length of time that the otoreseid treatment is continued end the teui3'-ioreture employed during such treat- 'nicht in somo instances ull the in KGO for forming lamp-filaments may be mixed and subjected to the high temperature and pressure or the said ingredients may be treated singly. It will thus be possible to so change the constitution of the carbon or other ingredients as to render them highly advantageous for the filaments of electric lamps. ln any case the temperature to which they are subjected is higher than that to which they will be subjected in the lamp itself.

The carbon obtained or the ingredients treated by my method are afterward reduced to extremely iine powder, mixed with suitable vehiclessuch as tar, pitch, or sugarand then molded into filaments, which are retorted and dashed in the usual manner. It will be obvious from what has already eeen stated that the electrical resistance of the filaments will be in proportion to the quantity of the diamond-carbon employed in their manufacture.

In the accompanying` drawings, Figure l is a side elevation, Fig. 2 a vertical section, and Fig. 3 a plan, of one form of the apparatus for use in obtaining a high pressure and temperature according to my invention. Fig. i is a vertical section, and Fig. 5 a sectional plan, ofa modiiied construction ofthe said apparatus.

Referring more particularly to Figs. l to 3, A is a strong vessel of approximately cylindrical shape, furnished with trunnions A A', by which it is pivotally supported in a frame A2. This vessel is preferably made 01": steel lined with suitable refractory material, such as bricks of compressed silica or compressed magnesia, to protect it from the heat to which it is subjected internally when in use. The ends of the saidvessel are provided with strong detachable screw-covers or screw-stoppers AiI A", each of which has a lever-handle A5 to enable it to be conveniently unserewed when either of the said covers is required to be removed for the purpose oi obtaining access to the interior of the vessel.

B ll' are carbon pencils or electrodes mounted in metallic holders l) (i, forming part of hollow stems h2, that extend through the aforesaid covers A Al. The carbon pencils are arranged coaxial with the vessel A, one et them being capable of longitudinal movement with respect to the other, so that the distance between their' adjacent ends can be varied according to requirements. For this purpose the stem b2 of the holder l) passes through a stu [hug-box a, forming part et' the plug-piece a. This stem b2 is connected at its outer end with another stem U, which is screw-threaded and passes through a nut bi. The said nut is mounted in a cross-piece L, so as to be capable of revolving without sliding, the cross-piece lf being connected by bolts b" to a disk or bar a2, which is screwed to the aforesaid plug-piece a and secures the latter to the cover A. The nut D! is furnished with lever-handles D7 to permit of its being revolved, while the stems b2 b are prevented from revolving by a feather bs on the carbonholder engaging with a longitudinal groove a3 inthe plug-piece. This plug-piece is insulated from the surrounding metal by suitable insulating material al. The other carbon pencil B' is carried by the stationary holder h, the stem b2 ot which passes through the screwplug A'1 and is insulated therefrom by insulating material Zi, such as mica or asbestos. In order to keep the carbon-holders cool, l make the said stem h2 b3 of the movable holder b and also the stem b2 of the iixed holder Zi hollow an d arrange within them a central pipe oi tube bw with au annular space L around it. The extremities of the stems are provided with inlet and outlet nozzles hw bw, one of which communicates with the pipe bm and the other with the annular space bl. Cold water can thus be allowed to circulate through the carbon-holders and the parts directly conneeted therewith.

The apparatus illustrated by l and 5 is provided with a lining A, upon which the vessel A is shrunk, the said lining having a spiral watercourse AT around it for the circulation of cold water, which enters at A and esca-pes at A". The plug-piece a' is likewise formed with a hollow head ci, communicating with longitudinal passages a" and with inlet and outlet nozzles 1T aS for enabling` cold water to circulate through said plug-piece and keep it cool. The screw-stopper Ai is in this example provided with an obturator AX, composed of asbestos and plumbago with a slight admixture of paraffin-wax Vfor assisting in rendering the vessel A gas-tight. lt is also provided with a toothed segmental portion A", adapted to gear with a worm i ll, mounted on an axle furnished with a crank-handle Al for revolving it. The said upper stopper A is formed with interrupted scrcw-threads, so that by giving approximately a (piarter-turn thereto it will be released from engagement with the corresjomling interrupted screw-threads on the vessel A. To permit ot it then being readily removed 'from the vessel, the said worm and the crank-handle are adapted to be disconnected by forming the worm with a longitudinal central hole el rec` tangular shape to receive the axle, which is also of rectangular shape at the part where the worm Hts it. The end Am of the said. axle and the portion A11 are made cylindrical to tit the bearings A15. .Vhen the axle has been revolved a sufficient number of times to turn and release thc stopper, as aforesaid, the said axle can be withdrawn longitudinally from the bearings A15 and also i'rom the worm, whereby both these parts are at one operation detached from the vessel A.

In using the apparatus the carbon er hydrocarbon is placed within the vessel A, together with a quantity of carbonic acid, preferably in its solid or snow-like condition. The vessel is then hermetically scaled by tightly screwing en the screw-Stoppers, and the electric current is then allowed to pass between IOO ITO

. cisnes the carbon pencils. As the tempe 1ature rises by the heat generated by the electric current the solid carbonio acid in the presence of the carbon Will be converted into carbon monoxid and a great pressure be thereby generated Within the vessel, as aforesaid. The continuance of such high temperature and great pressure will convert the carbon into a very hard `and crystalline condition, which after its removal from the vessel is crushed into line powder for use with the carbon employed in the manufacture of the filaments, as already explained above.

l do not confine myself to the use of the said apparatus for obtaining carbon in a hard and crystalline condition, as above stated, as the said apparatus may be used for treating other substances requiring to be subjected to high temperature and pressur. For instance, ordinary lamp-filaments after being retorted in the usual manner may be treated in the apparatus so as to hcat'them to a much higher temperature than is possible when they are heated at atmospheric pressure. in this case I prefer to employ a helloW carbon conductor to contain the filaments.

I do not claim herein the method described of inanufacturing` filaments for electric lamps, the same having been made the subject-matter of an application illed by me January 5, 1899, as a division hereof and bearing Serial No. 701,226.

'Vhat I claim isl. Apparatus consisting of a vessel provided With trunnion-bearlnOs to permit of its moving in a vertical plane, of a screw-cover for hermctically closing` said vessel of an electrically-insulated plug therein, of a hollow head to said plug` communicating with inlet and outlet nozzles through which Water enters and leaves the hollow head to keep the latter cool, of electrodes mounted in. holders located at opposite ends of said vessel, of stems on said holders extending to the exterior of the said vessel and for red with passages communicating` with the holders and with inlet and outlet nozzles through which Water enters .and leaves said holders te lteep them cool, of

a nut carried in a frame and engaging with screw-threads on one of the stems of the elec trede-holders, of handles on said nut for turning it and thereby shifting the holder so as to .adjust the distance between the electredes, of a lining` for said vessel such lining having,I a spiral 'watercourse for the entrance and exit of cold Water, and of a source of electricity for supplying electric current to the electrodes, substantially as and for the purpose speeiiieth L ln an apparatus consisting of a vessel capable of being1 hernietically closed by an interrupted screw-cover and having' elecn trodes mounted in adjustable holders te which electricity is supplied 'from a suitable source; the combination with the said vessel of a toothed segment on said cover7 of a crank-spindle having,` a rectangular portion7 of a worin adapted to loosely lit said rectaun guiar portion and engage With the teeth of the said toothed segment on the cover, and of brackets 'to temporarily receive said cranlspindle when the cover is operatedsubstauu tially as and for the purpose described,

ln testimony whereof l have hereunto set my hand, in presence of two subscribing \vitnesses7 this 7th day of November, 1898,

llllilfilii S'llflillilf lxlAXlhh lflituesscs:

Pannuti W. liter; lirri'ra'rnv C. lriusstirun, 

